File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

CSV file extension

Comma Separated Values File

Data Files

AIF file extension

Audio Interchange File Format

Audio Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

RAR file extension

WinRAR Compressed Archive

Compressed Files

CPL file extension

Windows Control Panel Item

System Files

FON file extension

Generic Font File

Font Files

DBF file extension

Database File

Database Files

DOCX file extension

Microsoft Word Open XML Document

Text Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

DLL file extension

Dynamic Link Library

System Files

3G2 file extension

3GPP2 Multimedia File

Video Files

7Z file extension

7-Zip Compressed File

Compressed Files

WAV file extension

WAVE Audio File

Audio Files

EPUB file extension

Open eBook File

eBook Files

AI file extension

Adobe Illustrator File

Vector Image Files